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M101 C11@F/7


The_Sarge

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My attempt at M101 with the C11 @F/7 with the STT-8300m and Baader filters

All images 2x2 binned.

124*300s Lum

20*600s each RGB

21*600s Ha

For a total of nearly 24 hours.

Processed in Pixinsight.

M101_PinwheelGalaxy.thumb.png.641a79b2deabab7415a46b0ea78ee58a.png

 

All comments and suggestions welcomed.

 

Sarge.

 

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24 minutes ago, MarsG76 said:

That is a amazing image.. over 3000mm FL is fantastic.... what mount are you using?

 

Mars,

I'm using Celestron CGE Pro Mount on a fixed pier in an observatory.

Alas the C11 with the 0.7x reducer is only 2000mm focal length and seems ok with PHD2 dialled in.

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2 minutes ago, The_Sarge said:

Mars,

I'm using Celestron CGE Pro Mount on a fixed pier in an observatory.

Alas the C11 with the 0.7x reducer is only 2000mm focal length and seems ok with PHD2 dialled in.

Now everyone knows that I failed maths!! :-/

That CGE Pro is obviously great.... I have a CGEM on a peir and it performs quite good at 2000mm on my 8" SCT so that CGE Pro tracking accuracy has to be very good, I'd assume sub 0.1" RMS since I'm getting 0.39" on the best nights. 

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3 minutes ago, MarsG76 said:

Now everyone knows that I failed maths!! :-/

That CGE Pro is obviously great.... I have a CGEM on a peir and it performs quite good at 2000mm on my 8" SCT so that CGE Pro tracking accuracy has to be very good, I'd assume sub 0.1" RMS since I'm getting 0.39" on the best nights. 

It's good but I wouldn't say great. There's a fair amount of backlash and Periodic error. I bought it as part of a deal with the C11 mainly because of the payload capacity.

As for RMS  on the guiding I get 0.2" as standard.

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All I really did was use the drift align to get my polar alignment to sub 1 arcmin and the run the guiding assistant for 5 mins and do what it told me to.

Made a massive improvement to the RMS came down from about 0.6" to around 0.2 -0.25"

Always tends to go a bit downhill after the merdian flip.

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11 hours ago, The_Sarge said:

All I really did was use the drift align to get my polar alignment to sub 1 arcmin and the run the guiding assistant for 5 mins and do what it told me to.

Made a massive improvement to the RMS came down from about 0.6" to around 0.2 -0.25"

Always tends to go a bit downhill after the merdian flip.

Probably because of backlash, depending if you made your setup east heavy - switching side of pier changes also heavy side. Maybe removable small weight that you add after meridian flip would improve things?

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6 hours ago, vlaiv said:

Probably because of backlash, depending if you made your setup east heavy - switching side of pier changes also heavy side. Maybe removable small weight that you add after meridian flip would improve things?

Thanks.

 

I'll look into that more. I do tend to keep it neutral rather than have one side heavy.

 

Sarge.

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Very good indeed and a great call on the binning.

I'm looking very carefully at resolution on M101 at the moment for a magazine article and coming to the conclusion that there are various ways of getting to the same place. Looking carefully at your core I think that it would be extremely hard to do better with 'real world' amateur instruments. Great stuff.

Olly

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12 hours ago, ollypenrice said:

Very good indeed and a great call on the binning.

I'm looking very carefully at resolution on M101 at the moment for a magazine article and coming to the conclusion that there are various ways of getting to the same place. Looking carefully at your core I think that it would be extremely hard to do better with 'real world' amateur instruments. Great stuff.

Olly

Thanks Olly,

Even binned the pixel scale is 1.14"/px which is way beyond the seeing up here in North Yorkshire on the best of nights.

It seems the 10hours of luminance subs paid off in the end. It responded well to a bit of deconvolution and a light touch with the unsharp mask.

I'm really quite pleased with what has been resolved in the core and the spiral arms.

 

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